Capsule forming gelatin film stripping



Dec. 25, 1956 F. E. STIRN ETAL CAPSULE FORMING GELATIN FILM STRIPPING 6Sheets-Sheet 1 Original Filed March 23, 1948 ATTORNEY Dec. 25, 1956 F.E. STIRN ETAL 2,774,938

CAPSULE FORMING GELATIN FILM STRIPPING Original Filed March 23, 1948 6Sheets-Sheet 2 mm W WEI

INVENTOR5 Pfl/VA JT/PNI. VP 6. 7-4/4 05) ATTORNEY INVENTORS Dec. 25,1956 F. E. STIRN ET AL CAPSULE FORMING GELATIN FILM STRIPPING 6Sheets-Sheet 3 Original Filed March 23, 1948 BY W W ha f ATTORNEY Dec.25, 1956 F. E. STIRN ET AL 2,774,988

CAPSULE FORMING GELATIN FILM STRIPPING Original Filed March 25, 1948 6Sheets-Sheet 4 BY WWW M ATTORN EY 6 Sheets-Sheet 5 F. E. STIRN ETALCAPSULE FORMING GELATIN FILM STRIPPING Dec. 25, 1956 Original FiledMarch 23, 1948 'IIIIIIII I n. n 4' .l

INVENTORS FP4/VA 'f. 6771 4/?77/4/4 6. 7-4/1 0 Dec. 25, 1956 F. E. STIRNET AL 2,774,988

CAPSULE FORMING GELATIN FILM STRIPPING Original Filed March 23, 1948 6Sheets-Sheet 6 ATTORNEY United States Patent CAPSULE FORlVIlNG GELATINFILM STRIPPING Frank E. Stim, Pearl River, and Arthur S. Taylor, SpringValley, N. Y., assignors to American Cyanamid Company, New York, N. Y.,a corporation of Maine Original application March 23, 1948, Serial No.16,554, now Patent No. 2,663,128, dated December 22, 1953. and thisapplication April 27, 1953, Serial No,

2 Claims. (Cl. 18-15) This invention relates to a method and apparatusfor stripping soft gelatin strips from a casting surface on which thestrips are formed; particularly by repeatedly striking the soft stripgentle blows with a counter-rotating paddle wheel.

This application is a division of our co-pending application SerialNumber 16,554, entitled Method and Masoft gelatin strip from a castingsurface with a minimum of deformation of the gelatin strip.

It is an additional object of the invention to remove a soft gelatinstrip from a casting surface with a minimum of stretch in order thatsymmetrical soft gelatin capsules may be more easily formed from anessentially unstretched gelatin film.

It is a still further object of the invention to provide a soft gelatinstrip at such a rate and with such uniformity of stripping that the soformed gelatin strip is uniformly fed to the capsuling operation and ishomogeneous; without any undue local over-stretching which may resultfrom removing the gelatin strip from the casting surface by tensionalone.

Further objects, advantages and meritorious features will appear fromthe following description, appended H certain of the drive mechanismsfor the various gears,

cams and rollers.

Figure 3 is a pictorial view showing the paths of the plastic strips asthey pass through the machine.

Figure 4 is a top view of the sealing film turn-over mechanism.

Figure 5 is an elevation of a portion of the die roll structure showingtemperature control elements and the positioning mechanism of thefilling heads.

Figure 6 is a front view of the stator of the cavity die roll, showingthe pressure and vacuum chests, heat control, etc.

Figure 6a is a side view of the stator.

Figure 7 is an enlarged view of a single die of the die roll and itscooperating filling head.

Figure 8 is a pictorial view of a filling head.

Figure 9 is a view showing the various coordinated phases of the diewheel operation.

Figure 10 is a fragmentary view onan enlarged scale taken along the line1010 of Figure 9, showing the ice Figure 11 is a similar view along theline 11-11 of Figure 9showing the die cavity containing the deformedlower film with the filling head in filling position as the powder flowsinto the cavity.

Figure 12 is a similar view along the line 1212 of Figure 9 showing thefilled individual cavity as the upper sealing film is positionedthereover.

Figure 13 is a similar view along the line 1313 of Figure 9 showing thejoining and cutting out of portions of the two films to form theindividual capsule.

Figure 14, along the line 1414 of Figure 9, shows the air ejectormechanism whereby the capsule is ejected from its mold, showing moreparticularly how the capsule rounds out as it is ejected, forming with asubstantially equatorial joining line.

This improved apparatus is designed to rapidly and efficiently producecapsules of consistent size. In the past it has been common to producesoft gelatin capsules filled with liquid or with pastes. If solids wereto be encapsulated, such solids were dispersed in a liquid to form apaste so that the materials could be filled on the then existentmachines.

With the development of purer and more potent vitamin products, the useof materials such as fish liver oil has given way to the use of moreconstituents of vitamin capsules in solid form. Many of the vitamins arenow obtainable or maybe converted to a particulate form, and their usein a powdered form possesses certain conveniences and therapeuticaladvantages, the full commercialization of which has been handicapped bythe lack of a suitable encapsulating machine.

The use of powders has long been known in hard gelatin capsules, inwhich the capsule body is first formed, then filled, and then a capplaced thereupon. The prior art has been uniformly unsuccessful inproducing satisfactory, adequate, and cheap machines for the fillingofpowders into soft gelatin capsules. Our machine fills the need. It willrapidly, easily and accurately form such powder filled capsules. Thismachine can be readily and conveniently adapted to fill liquids orpastes or can be used with films of material other than gelatin, if suchmaterials are plastic, are capable of being formed into films, and ifsuch films will unite with each other when passed through sealing rolls.

More. particularly, in our machine, molten gelatin as described-below,is prepared and fed into the hopper 21.

. For temperature control it is desirable that the hopper be equippedwith a thermostatically controlled heater element 21h so that thegelatin may be kept at a desired temperature. If the hopper isconstructed of brass the heat conductivity of the material will enablethe heat to be applied at one location, as shown in Figure 1. If othermaterials of construction are used, a more uniform distribution of heatover its surface may be desirable. A jacketed hopper may be used with asuitable fluid heat transfer medium. The hopper 21 may be filled by agelatin supply line 22 connected to a suitable source by which thegelatin in the hopper is maintained at a reason ably uniform level. Thegelatin hopper may be equipped with a transparent plastic top or itselfbe of transparent materials in order that the gelatin level may beobserved,

- but yet maintained free from danger of contamination,

' wheel 24, which wheel is formed preferably from a metal lower film inpositon over the die cavity.

suchas cast iron 'which should be given a highly polished surface, asfor example by chrome plating. .The hopper with the attached doctorblade is preferably adjustably 'locatable by means of links 25 and 26and adjustable shoes or rollers 21s, riding on the surface of thecasting amas roll so that the thickness of the gelatin film may beconveniently regulated. The hopper may be rigid if the doctor bladefloats in the desired relationship to the drum surface.

The doctor blade may be divided vertically inthe center and eachdivision made independently adjustable so that two separate thicknessesof film maybe cast at the same time so that the two different films'willeach be of independently adjustable thickness. This individualadjustability is of value in adjusting .the position of the equatorialseal and in insuring that the wall thickness of the different portionsof the capsule will be'in accordance with the operators desires.

The gelatin film is split into two portions by a splitting roll 27 whichis a reasonably sharp rotatable knife, spring loaded by an adjustablespring mechanism 258 so as to separate the cast film into two separatestrips. The split.- ting roll may be located adjacent to thege'latinhopper as shown, or may be located further around the casting wheel. Itis only necessary that the gelatin film be somewhat solid at thesplitting point, so that the gelatin will not how back together afterbeing split.

The entire mechanism is best located in an air ,conditioned room so thatboth temperature and humidity may be controlled so as to maintain thegelatin 'filminthe desired condition throughout. The casting wheel iscovered with a shield v2 9 which is located so that it :is adiacent tobut does not interfere with the rotation of the wheel. An exhaust ductisprovided through which the air is eX- hausted so that dry conditioned:air from the room is pulled through .the casting wheel shield 29 whereitdries and conditions the surface .of the gelatin film, and isexhausted either into the room Oran exhaust duct, depending uponmoisture load conditions. The casting Wheel is suitably supported from amain frame 31 and driven in suitably timed relationship with the rest ofthe mechanism by a mechanical drive means.

The partially dried and conditioned gelatin strip is removed from thecasting wheel by a stripper paddle 33. The stripper paddle is driven bya belt or other suitable drive at a faster speed than the peripheralspeed oflthe casting wheelzso as to pull off the gelatin film by itsaction. The repeatedsoft blows ;of the leading edges of this paddle asthe paddle is rotated has a tendency to strip the gelatin film withoutdamaging or stretching the film. It is highly advantageous in theproduction of spherical capsules that the gelatin film be not'stretched.

Undercertain operating conditions as is later described, it is desiredto stretch markedly the gelatin film by keeping it-under tension,.andforming the capsule While under tension. Under such conditions, astripping roll may be substituted for the .paddle. When so formed thegelatin strip material attempts to ,pull back ':to its original shape torelieve the strain' and accordingly, elliptical capsules are producedfrom round :molds. If elliptical shaped capsules' are desired,they may'be'produced in round dies by prestretching the film. Under-the normalrelationships, whereiit is desired that .a round die cut aroun'dcaps'ule, it is accordingly equally desirable that the gelatin:film be not stretched and remain substantially isotropic, so that thefinished capsule willn etain the desired shape.

As shown particularly clearly in Figure 3, the two gelatin stripstakeseparate paths from the stripper paddle. The sealing film 34 goes :abovethe die roll and may .be supported over guide rolls 35 and 36.0n whichmay be placed a carrier belt.:3,7. The carrier'belt and rollers shouldbe of a material which will not stick to-the gelatin. It ispossible.andlfrequently convenient to use rolls made from Teflon(Polytetrafluoroethylene,.see :U. S. Patent No. 2,230,654 to Plunkett),or from sintered metals which arefed withan oilerto-form oiledsurfaces-to whichthe gelatin strip willinot adhere. If several:rollersare used, a carrier belt is not tnecessary.

.Afterpassingtover'these guide membersthe strip itself is fed under and..over aturnoyer mechanism :38. It has e n found that for the e t s infi to p nsrl adhere to the lower film it is necessary that the castingwheel side of the gelatin sealing film 34 be placed in juxtapositionwith the casting wheel side of the lower strip 44. The outer face of thestrip forms a toughened and hardened surface, apparently from theevaporation of the moisture therein, so that it is not nearly asadhesive as the protected side ofthe strip. The outer tough side sealsonly with difiiculty, and such a seal is more fragile and shows agreater tendency to split.

The turnover mechanism as" illustrated, consists of two suitably.jo'urnaled rollers 39 and 40 on a shaft parallel to the die roll axisand two suitably journaled rollers 41 and 42 on an axis perpendicular tothe previously mentioned axis and thereabove, so that a belt 59traveling over these pulleys in the order 40, 42, 39, 41 and back to 40will pick up the film as shown in Figure 3, lift the same through to avertical direction, rotate through 90, reverse the film into anothertwist of 90 so that the film is fed out of this turnover mechanism .withthe casting roll side reversed, and shifted laterally so that this filmis now in the same frontal plane as is the lower film. The guide rolls35 and 36 may be driven by a suitable drive system 43 as is shown moreclearly in Figure 2. Some of the rolls may be driven by traveling belts,as for example the carrier belt 37, or the turnover carrier belt 50.Certain of the rollers may indeed be allowed to be idler-s if they arejOlllIlZllfid on comparatively friction free bearings so that thegelatin film itself will cause such guide rolls to rotate.

The lower strip of the gelatin 44 is, after being stripped from thecasting wheel by the stripper paddle 33, fed over guide rolls 46 and 47.Guide roll 46 may be oiled by means of a brush 45, rotating in a shallowbath of oil. Alternately this guide roll may be made 'of foraminousmaterial, as for example sintered brass, through which oil is fed from asuitable feed mechanism. it is desirable that'a .thin film of oil bemaintained on the surface of this roll so that the outside surface ofthe gelatin film is oiled so that it will not adhere as readily to laterportions of the mechanism. The guide roll 46 is preferably driven by asprocket drive 48, shown in Figure 2, so that the surface speed of thepulley is substantially the same as the surface speed of the castingdrum. The roll 47 is driven from roll 46 by a crossed belt roll drivesystem '32. The lower strip of gelatin 44, thence passes to the cavitydie roll 49.

The cavity die roll is a most important feature of the instant machine.The cavity die roll is designed with a plurality of .cavitiesin itsperipheral surface, each cavity forming a single gelatin capsule witheach rotation of :thecavity wheeL The individual capsule charge isplaced in this cavity and it is important that the machine work doneinforming the cavitydie wheel be of a high order :so -t-hat-thecavitieswill be of precisely identical dimensions. The consistency of successivecharges and the consistency of .the'size of the filled capsules depends,to a large extent, upon the accuracy of this cavitydie wheel. The exactnumber of cavities in the face of the die wheel is not of criticalimportance except to the extent that it determines the number ofcapsules .filled ineach revolustion. Asshowninthe sketch in Figure '3,there are'three rows of cavitiestin staggered relationshiparound thepeiriphery of the Wheel. A single row or any number of rowstmay be .usedas desired. There may be any desired number of cavities per row aroundthe circumference of the cavity die roll. Forillustrative purposes thereare :48 cavities shown in each row in the accompanyingdraw ings. Asshown more clearly in Figure'7, each cavity 51, which serves as .afilling chamber is cylindrical in nature and-hasaraised rim 52. Theraised rim preferably has a width of approximately one to two times thethickness of the gelatin strip. For small size capsules a width of '0;030 inch has proved satisfactory. The height of this raised rim 52, abovethe surface of-the cavity roll should be at least twice and preferablyabout three times the thickness of the individual gelatin film. Thecavity' roll surface 53 is in general the surface of a cylinder butits'accuracy is not particularly critical. The surfaces of the raised rimare necessarily very accurate as this raised rim must contact thesealing roll at all portions, during rotation, to give a good cut-out ofthe capsule.

The cavities may be elliptical, hexagonal, square, or such other shapeas may be desired. The cavity may taper towards the bottom, although noparticular advantage is found therein. Such modifications are within thescope of the invention, but are not frequently useful, as the complexityof the machining operations involved usually outweighs the advantages.

Each cavity has inserted therein an ejector plug 54. For cylindricalcavities this plug is cylindrical in configuration With a rim 55thereon. These plugs fit loosely into a plug retainer 56. The plugretainer should fit rather snugly into the cavity so that it will retainits position therein during operations. It may, of course, be held bypins, set screws, or other suitable means if desired, but with goodmachine shop facilities available it is usually cheaper to merely makethis plug a press fit. Either the rim of the plug or the bottom of thecavity should be slightly rough or serrated as shown at 57, so that theplug can not seal tight against the bottom of the cavity. The bottom ofthe cavity has an air duct 58 leading from its bottom through the cavitydie rolls to pressure and suc-. tion chests, as later described. Inoperation the plug should be of such height that when in its lowerposition it is substantially even with the upper surface of the plugretainer, so that the filling cavity is a fiat bottomed cylinder. Thedepth of this cylinder determines the depth of the fill for eachindividual capsule and should be consistent for all the cavities in thecavity die roll. This is best obtained by using precise machineoperations throughout the construction of the cavity, the ejector plugand ejector plug retainer. There must be sufficient clearance aroundthe'edges of the plug so that air from the air duct 58, can raise theejector plug until its rim contacts the retainer and is thus held in araised position by air pressure and so that air may be evacuated fromthe cavity during the evacuation portion of the filling cycle. It isdesirable but not necessary that the plug come to approximately the topof the cavity when raised by air pressure as it aids in the ejecting ofthe capsule. The cavity rim may be built up or the rim and the plugretainer made integral and screwed into the surface of the die roll, orsuch other construction used as may be more convenient under particularmanufacturing conditions, with equipment available.

The individual cavities should be fairly accurately spaced around theperiphery of the cavity die roll for convenience, as shown in Figure 3.The cavity rolls should be accurately and firmly journaled, as forexample by roller bearings upon a very solid shaft, or the shaft shouldbe solidly journaled upon appropriate bearings, because pressuresinduced by air pressure and vacuum applied during the filling operationsmay otherwise cause deflection, undue friction, and chattering of thisroll.

By suitable manifolding means, as for example illustrated by Figure 6a,the inside of the cavity die roll 49, has a die roll stator 103containing a suction chest 59 in contact with the interior surface ofthe cavity die roll so that air is evacuated through air duct 58, duringsuitable portions of the filling cycle. Air pressure acts through duct58 during other portions.

This is most easily arranged by a stator 103 in which is arranged thesuction chest 59 which has as an integral part thereof manifolding meanssuch that suction is applied over the desired portion of the fillingcycle, i. e. from the point 10-10 to 13-13 as shown in Figure 9. Thesuction may be applied through a suction connection 104. Air pressure isapplied through the air pressure lead 105, which supplies pressure sothat the ejector plugs 54 are raised at approximately the point 1414,shown in Figure 9. The use of multiple air blasts, by manifoldingasshown, is particularly effective in clearing the cavities. A springloaded sealing member 106 may be used to separate the vacuum from thepressure chests, which member may float in the stator so that any wearor unavoidable irregularities in the internal surface on the die rollwill be I compensated.

Whereas it is possible to use a stationary shaft upon which the statoris locked, for convenience of drive though the die roll is solidlyattached to the axle 75, which is gear driven, and the stator is keptfrom rotating by a stator positioning'pin 128.

For temperature control of the die roll it is particularly convenient toinstall heating members in this stator, which may well be of brass.Leads to this heating element are shown diagrammatically at 102. Fortemperature control it is desirable that the temperature of this statorbe controlled, as by a thermostat. Leads to a thermostat are shown at107. Any suitable type of thermostat may be used, including either onewhich is integral and individually adjustable or one may be used inwhich thermocouple leads are taken to an outside control. Manyvariations of temperature control will be obvious to those skilled inthe art, and the exact type of thermal control is not an essentialfeature of the instant invention.

As shown in Figures 3 and 1, there are positioning pins Won the frontsurface of the cavity die roll which pins are accurately positioned withrespect to the cavities and are used for the positioning of the fillinghead. In the particular configuration shown there are sixteen pins forforty-eight holes so that three sets of cavities, that is three cavitiesin each of the three rows, are'filled with each stroke of the fillinghead. The filling head block 63 is arranged to function in timedrelationship with the cavities so that during operation it performs acyclic shift whereby it is lifted from the surface of the cavity roll,

shifted backwards and allowed to drop to position, being accuratelypositioned by the pins 60 and remaining in contact with the cavity rollmechanism during a suitable portion of the rotation of the cavity wheel,after which it is raised to repeat the cycle.

The individual filling heads are shown in Figure 7.

Each of them consists of a cylinder 61 in which fits a filler assembly62. The filler assembly is positionable axially so that its lower edgeprojects 'below the surface of the filler head block 63 by an adjustableamount, usually equal to from 1 to 2 times the thickness of the film.The filler assembly 62. may be integral or built up and consists of acylindrical shell through which passes a filler passage 64. This fillerpassage extends from the supply means, as described later in a hopperthrough the filler assembly. Around the lower end of the filler assemblyis an annular space filled with a foraminous material 65. The foraminousmaterial may consist of felt, sintered glass or sintered metals. Forfilling routine vitamin products sintered metal is usually particularlyconvenient because it may be turned to size and even soldered or brazedin location so that the sizing is accurate, and it may be readilysterilized. From the upper surface of this foraminous material there ian exhaust duct 66. The exhaust duct leads into an exhaust annulus 67cut into the periphery of the filler assembly which is in turnpositioned opposite the exhaust manifold 68, which in turn is connectedto the exhaust tubing 80.

During the fill operations the filler head block 63 comes down intojuxtaposition with the gelatin film'riding on the cavity die roll 49.The exterior diameter of the filler assembly should be such that thereis suflicient clearance between it and the cylindrical surface of thecavity for the thickest gelatin film which is to be used with themachine. f

A plurality of these fillerv assemblies are positioned so that the 3 by3 block of cavities has a filler head in 7 each; The filler heads aremounted in a filler head block 3. 7

As shown diagrammatically in Figure 7, this filler head block maybeequipped with a filler block heater element 108, and a filler blockthermostat 1091 As mentioned elsewhere, any of the conventional types ofheaters and thermostats may be used. Electrical controlis particularlyconvenient. Heating of the block is not always necessary but it' isparticularly convenient, When the machine is used for hygroscopicpowders, as it keeps the block warm' so that moisture will not cause thepowder passages or the foraminous material to become clogged.

The filler head block hasmounted thereon a powder hopper 69. The powderhopper is preferably made of transparent material so that its contentsmay be readily observed. As shown in Figure l, the powder hopper has astirrer 70 mounted therein which consists of wires mounted on a shaftwhich is mounted in the top of the powder hopper and is turned by aflexible shaft 71 driven by a suitable source of power. The fillerpassages extend up to this powder hopper. It is desirable that thestirrer be" rotated" suffi'ciently rapidly to avoid caking or bridgingof the powder. If desired the powder hopper may be provided with a feedopening 72 in which. a flexible duct carrying additional powder may beinserted so that the hopper may be filled automatically or manually asmay be desired with additional powder during operation of the machine sothat the powder hopper is maintained sufiici'ently filled for constantoperation without shutdown. For satisfactory results it is necessarythat sufficient powder be maintained in the hopper at all times so thatno filler passage draws air instead of powder from the hopper.

The filler head block assembly is positioned in relationship to thecavity die roll by means of the eccentric die'roll, clockwise asillustrated, the eccentric 76 contacts the lower end of the lifting armin approximately the position as shown in Figure 6. At this point theeccentric lifts the arm substantially radially relative to the cavity"die block until the positioning. block 79 clears the positioning pin 69.As soon as this pin is cleared the friction and direction of motion ofthe eccentric pu-lls the-arm and the accompanying filler head blockassembly in" a counterclockwise direction in an elevated positionto;approxim'ately the position shown at the dotted line inFigure 5.Atthis point the eccentric pin having passed its top center and havingstarted downward, lowers the arm and the filler head block assemblyuntil the pins '61? pick up the positioning block 79' and cause theentire assembly to rotate clockwise again. As the block is rotatedclockwise the eccentric continues to drop until the entire weight of thefiller head block restsupon the positioningpins and/or the gelatin filmand cavity die roll, at which point the eccentric turns free in theeccentric guide.- opening: until time for the cycle to begin again.

- Anidentical mechanism is present on the back side of the cavitydieroll so that the powder hopper is supported both in front and in backby an-iden-tical symmetrical mechanism. It is usually most convenientthat this mechanism be behind the drive for the cavity die roll, Fornormal operations it-is desirable that the weight of the cavity blockrest on the gelatin film rather than on the positioning, pins, so thatthe gelatin film acts as a seal and prevents the leakage of air aroundthe periphery of the tiller; It is desirable but not necessary that thepositioning pins and positioning black bear a relationship such that ifthe gelatin film is removed by inadvertence; or at the beginning or endof'operation, the weight of the filler block is taken by the pins ratherthan by the" raised rims of the cavities. If the block' is allowed topound on the cavities with no, gelatin in between, the rims maybecomebatte'red.

By this mechanism and method the filler head block assembly is raisedduring the non-filling portion of the cycle and positioned again over anew set of cavities. Of course, the filler head block may have more orless filler heads to fil-l more or less cavities than shown peroperation provided that the pins are positioned for each group ofcavities as desired. Usually for the size capsules which are desired itis more convenient if more than one capsule be filled per row per cycle.As illustrated, three are filled. g

The gelatin strip is fed under the guide roll 47 and into contact withthe cavity die roll 49; As shown by the schematic Figure 9, this gelatinstrip is positioned on the die roll resting on top of the raised rims52. At the point shown by the line 10-10, Figure 9, the suctionmanifoldadmits suction to each cavity through the air ducts 5 8 whichcauses the gelatin film .to be pulled tight against the raised rim 52and drawn down therein to form a cup shaped lining in the fillingchamber 51. Figure 10* shows the lower film positioned on the raised rimand Figure 11 shows the film having been pulled down into contact withthe ejector plug and plug retainer. The suction is maintained on thechamber until after the capsule is sealed and cut-out. Usually a higherdegree of vacuum is maintained under the gelatin film than is used aboveit in the filling operations.

As" the gelatin lined chamber advances the filler head block is loweredinto contact therewith, as described above, and shown schematically inFigure 11, taken on line 1111-'. The filler assembly may enter partiallyinto the gelatin lined container. The filling. head itself preferablyrests on the gelatin film.

At this portion of the cycle, at about the point 1111 of Figure 9, thefilling occurs. The filled powder should be of such consistency inrelation to the size of openings that it will not flow through thefiller passage 64 under the influence of gravity and such vibrations asoccur, but instead, after the machine is in operation, blocks or bridgesacross the passage.

When the filler assembly is in position, vacuum is applied through theexhaust manifold 68; To insure adequate and proper filling, it isdesirable that the air be evacuated through the passage 63 in slugs.This is accomplished by connecting the exhaust tubing 80 to a solenoidoperated valve which is connected to a vacuum pump (not shown). Thesolenoid valve may be actuated by a microswitch 81, which has a contactmember I 82, riding upon actuating pins 83, on a cam plate 84.

These contacting pins are so arranged that the solenoid releases the airthrough the exhaust duct 68 into the vacuum pump in bursts which gives apulsating flow to the powder and causes it to compact to a uniformdensity in the filling chamber. The foraminous material 65 prevents thepowder from flowing through the exhaust ducts and-insures acomparatively uniform and consistent density of the powder. Under normaloperating conditions, if subjected to a series of bursts of vacuum, fivebeing a suitable number although from a single burst to as many as adozen (for different powders) may be used if desired, a-powder may becompacted to a remarkably uniform density. It has been found thathomogeneous powders will be normally compacted by such an. arrangementso that the density of a charge will not ordinarily vary more than afraction of one percent. If the charge chambers are of consistent sizeand the gelatin film is cast to a consistent thickness, this will meanthat the individual chambers will be filled uniformly so that the finalcapsules containequal dosages.

I The size of these charges may be adjusted by varying the amount whichthe filler assembly 62 projects into the charge chamber, or by varyingthe depth of the 'charge chamber. Some variation may be introduced byvarying the pressures and vacuums used.

After the filling operation is completed, and the vac- .uum is released,the filling head block assembly is lifted by means of the cam andlifting arm, as explained above, the filled chamber rotates past thepoint shown by 1212 as shown by the sketch in Figure 12, at which pointthe sealing film 34 is brought into juxtaposition with the filled chargechamber by the sealing roller 85. The sealing roller 85 is springmounted by a sealing roll spring assembly 89 so that the pressurebetween it and the cavity die roll may be readily varied and so that anyirregularities may be compensated by spring action.

As shown in Figures 3 and 5, this sealing roll may have small aperturestherein, conveniently though not necessarily mated to match with thecavities in the die roll, through which vacuum is applied as by themanifold 111 and the vacuum connection 110. The suction through theseorifices assists in positioning the sealing film so that it will notslide unduly on the surface of the sealing roll. If the particulargelatin compound used appears to stick to the sealing roll, an airpressure assembly, such as is used in the cavity die roll, may beembodied in the sealing roll to assist in releasing the gelatin film andcapsules from the sealing roll. As shown at 112, an oil fed wick mayrest upon the surface of the sealing roll, being in turn supplied by asuitable oil supply so that a thin film of oil is maintained on thesurface of the sealing roll at all times to prevent adherence of thegelatin to this roll. It will be found that if the roll is over-heatedthe gelatin is particularly apt to stick, and that if a gelatin mixrequires a higher temperature, particular care is necessary to insurethat this roll have a high gloss and be adequately oiled to preventsticking or building up of gelatin on the surface.

As more particularly shown in Figure 5, a heater member 86 is in contactwith the side of this sealing roll stator 113, and is thermostaticallycontrolled by means of a thermostat 87 so that the temperature of thisroll may be maintained as desired. Whereas the thermostat and the heaterare shown in a stator, they may be built as sliding upon the sidesurface of this sealing roll or the heater and the thermostat may bebuilt integral with this sealing roll and connections may be by slidingcontacts brought out through the axle if desired.

The stator is retained in position by the sealing roll statorpositioning pin 129 and its associated bracket 130. The temperatureadjustment of this roll may be critical as will be later described.

As the cavity die roll and the sealing roll rotate together, the springaction above described, first causes the sealing film 34 to contact thelower strip 44 and then to press upon this lower strip which in turn issupported by the raised rim 52, until the raised rim cuts into thecombined gelatin films, as shown at Figure 13. The compression actioncaused by this pressure causes the gelatin caught between the raised rimand sealing roll to be extruded and as it is pressed between thesemembers it unites with itself so that a sealed joint is formed. The twogelatin fihns under proper operating conditions are so uniformly unitedthat it requires inspection to locate the seal and the seal is nearly asstrong as the wall of the capsule. The residual web 88, is forced downon the outside of the raised rims 52 and into the space providedtherein. As the two rolls separate as they turn, air pressure may beapplied by means of a manifold under the cavity die so as to raise theejector plug 54 as shown in Figure 14, taken along the line 1414. Thisaction of raising the ejector plug causes the filled capsule to bepressed out of the chamber and allows it to spring to its natural shape.

To give a good clean seal and to cut the gelatin completely out of theweb it is desirable that the sealing roll spring assembly 89, presscomparatively firmly upon the surface of the sealing roll. If there areany irregularities in the rim, a small flash may remain which may causethe capsule to stick in the web, but under normal operating conditions,if the rolls are accurately made, the capsules will be completelydetached. As shown in Figure 1 and in Figure 9, the capsules afterpassing the line 14-14 have a tendency to be ejected by the plug and airpressure. This is followed by the action of two revolving brushes 90,which rotate in a counterclockwise direction at a comparatively highrate of speed, their peripheral speed being several times the surfacespeed of the cavity die roll. These brushes have an additional tendencyto throw the capsules upon a conveyor belt 91 which removes the capsulesto a discharge point. The web with the capsules cut on thereof is pulledaround the web roller 92 and through the web removal rollers 93, whichrollers are rotated at a slightly higher surface speed so as to pull theweb and stretch it so that it is easily removed. The web from this pointis fed to a waste container or otherwise disposed of. Other means may beused to remove the residual web, as frequently just gravity is adequate.Individual suction cups, brushes, and other methods shown in the priorart may be used.

The sealing roll spring assembly 89 may be any conventional universalassembly whereby the spring loaded sealing roller is permitted to run incontact with the gelatin contacting the cavity die roll. As shown, theaxles of these two rollers are maintained essentially parallel by theslots in the retaining frame 94. However, in and out motion in thedirection of the line of centers is permitted and occurs against thespring, compression of which is adjustable by means of the tighteninghandle 95.

Figure 2 shows in diagrammatic form the driving belt system for themachine. For normal operation, as herein described, it is desirable thatthe gelatin strip remain slack but not loose at all points. Tensionshould be avoided in the gelatin strip. This is most easily accomplishedby insuring that the surface speed of each of the gelatin contactingrollers is the same as the surface speed of the casting wheel. Normallythe gelatin film will have a tendency to shrink from drying after it isremoved from the casting wheel, but at' the same time will have atendency to stretch because of the warming of the gelatin and because ofthe natural weight of the gelatin tending to stretch it as it passesover the rollers. In general, it will be found preferable to drive therollers by positive means by either sprockets and chains or by directgearing. This automatically tends to stabilize the length of the castfilm. The number of teeth in each of the gears is not critical nor isthe size of the rollers, but they should be so related that the surfacespeed of all rollers be substantially uniform throughout; with theexception of rollers 93, the web removing rollers, which may be drivenat a higher speed to remove the film.

Because of the peculiar properties of gelatin, it has a tendency to beslowly elastic. If stretched, a film of gelatin has a tendency torecover its original shape slowly. Accordingly, if the gelatin strip isstretched at any point during its passage through the machine it willtend to recover to its original dimensions, though slowly. If desired,advantage may be taken of this characteristic by stretching the film bydriving the casting roller slower than the other rollers in the machine.If this is done, after the capsules have been cut and emerged from thedie roll as essentially spherical, the gelatin films forming the capsulewill shrink in the direction in which they were originally stretched insuch a fashion as to give a football shaped capsule. This casting ofelliptical capsules from round cavities is an important feature of thisinvention, but is not necessarily an essential feature; as if it bedesired to cast spherical capsules, by the same token, this same stretchmust be avoided.

As shown in Figures 1 and 2, a drive motor 96, through a worm gearsystem 97 drives the main shaft 98 which in turn drives the castingwheel by means of the casting wheel gear system 99. In the particularmodification shown, beveled gears 100 drive a jackshaft 101 on which aremounted sprockets for driving various parts of the machine. Each of therotating drive wheels is preferably driven in some fashion from apowered shaft with the exception of spring loaded roll 85, which maybedriven merely by contact because of the high pressure between it and thecavity die roll.

If mated vacuum openings 114 are used, the roll 85 should be geared orotherwise positively driven in timed relationship with the cavity dieroll as shown.

Only one drive pulley is necessary for each of the belted rollersystems.

Figure 2 shows diagrammatically certain aspects of a particular systemor roller drives which has proved satisfactory. It is readily Within therange of anyone skilled in the art to work out other methods of driveswhich are satisfactory for driving the various members at the speedsshown to be desirable elsewhere in this specification. As shown inFigure 2 from the jack-shaft 101 there is a main chain roller drive 115which drives the cluster shaft 116. From this cluster shaft by means ofa paddle drive belt 117 the paddle 33 is driven. By means of thesprocket drive 48 and an associated belt drive the guide rollers 46 and47 are driven from the same shaft. The turn-over mechanism is driven bymeans of a turn-over mechanism chain drive 118. The carrier belt 37 isdriven by an appropriate carrier belt drive 119. From the cluster shaft116 by means of a suitable idler gear 120 is driven the eccentric shaft77 and related mechanism, by an ecentric shaft gear 121. In turntherefrom, through idler gear 122 is driven the cavity die roll"'gear123 and in turn therefrom the sealing roll gear 124.

From the jack-shaft 101 by means of the web removal roller sprocketdrive 125 there is driven the web removal rollers and by an associatedbelt and pulley system functioning as a discharge conveyor belt drive126, the K discharge belt and associated mechanism is driven. From thisin turn is driven the revolving brush drive system 127.

The entire drive system is within the skill of the art and may bereadily modified in any number of various ways without departing fromthe scope of the invention. It is to be noted that, in the system asshown, by changing one sprocket in the main chain roller drive 115 andcoordinating the sprocket drive chain length therewith, it is possibleto change the speed relationship between the cavity die roll and allgelatin strip contacting members affiliated. therewith and the castingwheel itself, so that it is possible to readily arrange various degreesof stretch in the gelatin film when and if desired. If greaterflexibility is desired a variable speed drive system may be installed atthis point so that variations in the degree of stretch may beaccomplished while the machine is in actual operation.

Certain examples of the use of the machine are described in our abovementioned Patent 2,663,128.

As our invention, an improvement to the art of making capsules, weclaim:

1. An apparatus for the production of soft gelatin strip for capsulemanufacture, comprising a continuously moving casting surface, means forcasting a continuous gelatin strip thereon, a multibladedcounter-rotating paddle wheel adjacent said casting surface at thegelatin strip take-off point and contacting the gelatin strip, means forrotating said paddle wheel at higher peripheral speed than the speed ofthe casting surface, and strip conveying means drawing the strip awayfrom the paddle wheel, whereby the gelatin strip is repeatedly contactedby the leading edges of the paddles, and thereby pulled free from thecasting surface with a minimum of stretching.

2. In an apparatus for the manufacture of soft gelatin capsules, acontinuously moving casting surface, means for casting a continuousgelatin strip thereon, including a gelatin hopper, and support meansresting on said casting surface for said hopper, means for cooling andpartially drying the gelatin strip, a multibladed counterrotatingpaddle-Wheel adjacent said casting surface at the gelatin strip take-offpoint and contacting the gelatin strip, means for rotating saidpaddle-Wheel at a higher peripheral speed than the speed of the castingsurface, and strip conveying means drawing the strip away from thepaddle wheel, whereby the gelatin strip is repeatedly contacted by theleading edges of the paddles, and thereby pulled free from the castingsurface with a minimum of stretching.

References Cited in the file of this patent UNITED STATES PATENTS590,017 Evans Sept. 14, 1897 1,235,716 Mooney Aug. 7, 1917 2,116,916 VanHyning May 10, 1938 2,556,247 Zeigler et al June 12, 1951 2,654,123 HallOct. 6, 1953

1. AN APPARATUS FOR THE PRODUCTION OF SOFT GELATIN STRIP FOR CAPSULEMANUFACTURE, COMPRISING A CONTINUOUSLY MOVING CASTING SURFACE, MEANS FORCASTING A CONTINUOUS GELATIN STRIP THEREON, A MULTIBLADED COUNTERROTATING PADDLE WHEEL ADJACENT SAID CASTING SURFACE AT THE GELATIN STRIPTAKE-OFF POINT AND CONTACTING THE GELATIN STRIP, MEANS FOR ROTATING SAIDPADDLE WHEEL AT HIGHER PERIPHERAL SPEED THAN THE SPEED OF THE CASTINGSURFACE, AND STRIP CONVEYING MEANS DRAWING THE STRIP AWAY FROM THEPADDLE WHEEL, WHEREBY THE GELATIN STRIP IS REPEATEDLY CONTACTED BY THELEADING EDGES OF THE PADDLES, AND THEREBY PULLED FREE FROM THE CASTINGSURFACE WITH A MINIMUM OF STRETCHING.